TWI792988B - Voltage generating circuit and semiconductor device - Google Patents

Abstract

The disclosure provides a voltage generating circuit and a semiconductor device that can suppress leakage current without using a deep power-down mode. The voltage generating circuit of the disclosure includes: a reference voltage generating unit to generate a reference voltage; a leakage current monitoring unit to generate a leakage current corresponding to the leakage current of the peripheral circuit; a output voltage control unit controls the reference voltage according to the leakage current, and outputs the controlled reference voltage; a standby voltage generation unit, which according to the controlled reference voltage to provide an internal supply voltage to a peripheral circuit; and a voltage drop detector detects that the controlled reference voltage has dropped to a certain level. The output voltage control unit controls the controlled reference voltage based on the detection result of the voltage drop detection unit.

Description

Voltage generating circuit and semiconductor device

The present invention relates to a voltage generating circuit and a semiconductor device, in particular to a voltage generating circuit and a semiconductor device that suppress leakage current.

In a semiconductor device, a temperature-compensated voltage corresponding to an operating temperature is generally generated to operate a circuit to maintain reliability of the circuit. For example, in a memory, when reading data, if the reading current decreases due to temperature changes, the reading margin will decrease, and accurate data reading will no longer be possible. Therefore, by using the temperature-compensated voltage to read the data, the decrease of the read current is prevented. For example, Japanese Patent Application Laid-Open No. 2021-82094 discloses a voltage generating circuit that does not require an on-chip temperature sensor or logic for calculating a temperature compensation voltage based on the result, and reduces the circuit scale.

Semiconductor devices such as resistance variable memory can operate at low voltage and constant current, and are suitable for mobile devices such as the Internet of Things (IoT). When the range of application in mobile devices, etc. expands, the temperature range in the operating environment also expands. Therefore, a voltage generating circuit usually mounted in a semiconductor device can generate Compensated voltage.

FIG. 1 is a diagram showing an example of a conventional temperature-compensated voltage generating circuit. The voltage generation circuit 10 includes: a band gap reference circuit (BGR (Bandgap reference) circuit) 20 that generates a reference voltage Vref that is not related to fluctuations in the external power supply voltage; Vref to generate the internal supply voltage INTVDD.

The internal voltage generating circuit 30 includes an operational amplifier OP and a positive channel metal oxide semiconductor (Positive Channel Metal Oxide Semiconductor, PMOS) transistor Q1. The reference voltage Vref is input to the inverting input terminal (-) of the operational amplifier OP, and the voltage VN of the node N is input to the non-inverting input terminal (+) through negative feedback. The output of the operational amplifier OP is connected to the gate of the transistor Q1, and the load of the peripheral circuit 40 is connected to the node N. The operational amplifier OP controls the gate voltage of the transistor Q1 so that the voltage VN of the node N becomes equal to the reference voltage Vref (VN=Vref). In this way, the current flowing through the transistor Q1 becomes a constant current regardless of fluctuations in the supply voltage VDD, and the internal supply voltage INTVDD (INTVDD=VN) of a constant current is supplied to the peripheral circuit 40 .

For example, when the flash memory is on standby in the stand by mode, if the operating temperature becomes high, the leakage current flowing to the peripheral circuit 40 increases. Various integrated circuits using complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) transistors and the like are formed in the peripheral circuit 40, and the positive-negative junction (Positive-Negative junction, PN junction) leakage current of these circuits and the transistor Threshold leakage current increases with temperature. In addition, the leakage current is related to the electrical Therefore, when the internal supply voltage INTVDD increases due to external factors, the leakage current also increases.

In order to suppress the leakage current, some semiconductor devices adopt the deep power down mode (Deep Power Down mode, DPD mode), which can further reduce power consumption compared with the standby mode. In the DPD mode, the operation of the internal voltage generating circuit 30 is stopped, for example, a switch is provided between the supply voltage VDD and the transistor Q1, and Q1 is closed during the operation stop stage of the internal voltage generating circuit 30, thereby cutting off the supply voltage VDD. power supply.

However, the DPD mode has the following problem: when the supply voltage VDD is cut off by the DPD mode, the peripheral circuit 40 becomes floating (floating), and when recovering from the DPD mode, the circuit elements and lines of the peripheral circuit 40 must be adjusted. Waiting for the capacitor to charge, resulting in time-consuming and unable to quickly proceed to the next action.

In order to solve the above-mentioned problems, the present invention provides a voltage generating circuit capable of suppressing leakage current without using a DPD mode.

The voltage generation circuit of the present invention includes: a reference voltage generation unit that generates a reference voltage; a leakage current monitoring unit that generates a leakage current for monitoring corresponding to a leakage current in an internal circuit of a semiconductor device; to control the reference voltage; and an internal voltage generating unit that receives the reference voltage controlled by the control unit and supplies an internal voltage to the internal circuit according to the controlled reference voltage.

The semiconductor device of the present invention may include the voltage generator of any embodiment of the present invention Into a circuit, and including operation under low power consumption, the internal voltage can be supplied to the internal circuit in the standby mode.

According to the present invention, the reference voltage is controlled based on the leakage current for monitoring the leakage current of the internal circuit, and the internal voltage is supplied to the internal circuit based on the controlled reference voltage, so that the temperature-compensated reference voltage can be autonomously generated, thereby The leakage current of the internal circuit can be suppressed to a minimum.

10: Voltage generating circuit

100, 200, 200A, 400, 500: voltage generating circuit

110: Reference voltage generation circuit (BGR circuit)/reference voltage generation unit

112: Operational amplifier

20: Band difference reference circuit (BGR circuit)

210, 210A: reference voltage generating unit

220: Leakage current monitoring department

230, 310, 310A, 310B, 410: output voltage control unit

240: standby voltage generation unit

250: peripheral circuit

260:Active voltage generation unit

30, 120: Internal voltage generating circuit

300: voltage drop detection unit

320: voltage offset part

40: Peripheral circuit

BP1, BP2: bipolar transistor (PNP bipolar transistor)

IA, IB, IC, IN: leakage current

iBGR: the current flowing in the BGR circuit

I _LEAK : Leakage current

IN: Inverter

INTVDD: Internal supply voltage

IPMOS, INMOS: off-state leakage current (leakage current)

N, N1, N2, N3, N4, N5: nodes

OP: operational amplifier

OP1: Unity gain buffer

Q1, Q3, Q5, Q10, Q20: transistors (PMOS transistors)

Q2: Transistor

Q4: Transistor (NMOS transistor)

R1, R2, R3, R4, Rf: resistance

Trim: Trim the signal

VDD: supply voltage/power supply voltage/external power supply voltage/external supply voltage

Vref, Vref_NTc: reference voltage

Vref_C: reference voltage after control

FIG. 1 is a schematic diagram of a conventional voltage generating circuit.

FIG. 2 is a schematic diagram of a voltage generating circuit according to a first embodiment of the present invention.

FIG. 3 is a block diagram showing the structure of a voltage generating circuit of a second embodiment of the present invention.

(A) of FIG. 4A , (B) of FIG. 4A , (C) of FIG. 4A , and (D) of FIG. 4A are schematic diagrams of a leakage current monitoring unit according to an embodiment of the present invention.

(A) of FIG. 4B and (B) of FIG. 4B are schematic diagrams of a leakage current monitoring unit according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a voltage generating circuit according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing the structure of a voltage generating circuit of a third embodiment of the present invention.

7 is a schematic diagram of a first example of a voltage generating circuit according to a third embodiment of the present invention.

FIG. 8 is a schematic diagram of a second example of the voltage generating circuit of the third embodiment of the present invention.

Fig. 9 is a schematic diagram of a third example of the voltage generating circuit of the third embodiment of the present invention picture.

FIG. 10 is a schematic diagram of a voltage generating circuit according to a fourth embodiment of the present invention.

FIG. 11 is a schematic diagram of a voltage generating circuit according to a fifth embodiment of the present invention.

The voltage generation circuit of the present invention is mounted on semiconductor memories such as flash memory, dynamic memory, static memory, resistance variable memory, and magnetic memory, or semiconductor devices such as logic circuits and signal processing.

Referring to FIG. 2 , the voltage generation circuit 100 of the present embodiment includes a reference voltage generation circuit (BGR circuit) 110 and an internal voltage generation circuit 120 . The voltage generation circuit 100 is mounted in, for example, a flash memory, and supplies the internal supply voltage INTVDD to the peripheral circuit 40 when the flash memory is in a standby state. During this period, the peripheral circuit 40 is in the low power consumption mode, but when a command is input from the outside, etc., it operates in response to the command.

The BGR circuit 110 utilizes the band drop voltage, which is a physical property of silicon, a semiconductor material, to generate a stable reference voltage with low dependence on fluctuations in temperature and power supply voltage. The BGR circuit 110 includes first and second current paths between a power supply voltage VDD and a ground (Ground, GND). The first current path includes a PMOS transistor Q10, a resistor R1, and a Positive-Negative-Positive (PNP) bipolar transistor BP1 connected in series. The second current path includes a series connection of PMOS transistor Q11 (same structure as transistor Q10 ), resistor R2 (same resistance value as resistor R1 ), resistor Rf, and PNP bipolar transistor BP2. The BGR circuit 110 also includes an operational amplifier 112, wherein the connection node N1 of the resistor R1 and the bipolar transistor BP1 is connected to the terminal of the operational amplifier 112 The inverting input terminal (-), the connection node N2 of the resistor R2 and the resistor Rf is connected to the non-inverting input terminal (+) of the operational amplifier 112, and the output terminal of the operational amplifier 112 is commonly connected to transistors Q10 and Q11. gate.

The emitter area ratio of the bipolar transistor BP1 and BP2 is 1:n (n is a number greater than 1), and the current density of the bipolar transistor BP1 is n times that of the bipolar transistor BP2. Furthermore, although a bipolar transistor is exemplified here, a diode having an area ratio of 1:n may also be used instead of the bipolar transistor.

The operational amplifier 112 controls the gate voltages of the transistors Q10 and Q11 to make the voltage at the node N1 equal to the voltage at the node N2 , so that equal currents I _B flow in the first current path and the second current path. The voltage V _Rf between the terminals of the resistor Rf is represented by the following formula.

V _Rf =kT/qIn(n)

k is the Boltzmann constant, T is the absolute temperature, and q is the electric charge of the electron.

The current I _B flowing through the resistor Rf is represented by the following equation.

I _B =V _Rf /Rf=T/Rf×k/qln(n)

The temperature-dependent factor is T/Rf, and the current I _B has a positive temperature coefficient.

In addition, assuming that the resistance at the selected joint position of the resistor R2 is the resistor R2', the reference voltage Vref_NTc is represented by the following equation.

Vref_NTc=V _N2 +I _B R2'

V _N2 is the voltage of node N2.

In a preferred embodiment, resistor R2 comprises a semiconductor material with a negative temperature coefficient. That is, as the temperature increases, the resistance decreases, and vice versa, as the temperature decreases And the resistance increases. The resistor R2 is composed of, for example, a conductive polysilicon layer doped with a high-concentration dopant, and an N+ diffusion region. The reference voltage Vref_NTc can have a desired negative temperature coefficient by properly selecting the junction position of the resistor R2. The joint position or the negative temperature coefficient is determined according to how much reference voltage is supplied to the internal voltage generating circuit 120 at the expected maximum temperature.

The internal voltage generating circuit 120 has the same configuration as the internal voltage generating circuit 30 shown in FIG. 1 . 2, the reference voltage Vref_NTc generated by the BGR circuit 110 is input to the inverting input terminal (-) of the operational amplifier OP of the internal voltage generating circuit 120, and the voltage VN of the node N is input to the non-inverting input terminal ( +). The internal voltage generation circuit 120 supplies the internal supply voltage INTVDD generated from the reference voltage Vref_NTc from the node N to the peripheral circuit 40 .

In this embodiment, the flash memory does not adopt the DPD mode, that is, it does not change from the standby mode to the DPD mode, but the leakage current generated in the peripheral circuit 40 is suppressed to a minimum in the standby mode. While standing by in the standby mode, when the operating temperature becomes high, the reference voltage Vref_NTc generated in the BGR circuit 110 decreases due to having a negative temperature coefficient. The reduction of the reference voltage Vref_NTc causes the internal supply voltage INTVDD generated by the internal voltage generation circuit 120 to also decrease. The leakage current generated by the PN junction leakage of the peripheral circuit 40, the off-state leakage of the transistor, etc. increases with the increase of the operating temperature, but these leakage currents are related to the internal supply voltage INTVDD. If the internal supply voltage INTVDD decreases, the leakage current will increase. The current is also reduced accordingly.

In this embodiment, since the reference voltage Vref_NTc has a negative temperature range Therefore, if the temperature rises, the reference voltage Vref_NTc decreases to offset the increased leakage current of the peripheral circuit 40 . In addition, since the DPD mode is not employed, the next active action can be performed without considering the delay time for recovery from the DPD mode.

In the first embodiment, the resistor R2 must be trimmed during manufacture or delivery, so that the reference voltage Vref_NTc falls within a certain voltage range when the operating temperature rises. But in fact, the increase of the leakage current is not linear, but increases exponentially with a certain temperature as the boundary, so its trimming is extremely complicated. In addition, when the operating temperature exceeds the assumed temperature, the reference voltage Vref_NTc will deviate from the certain voltage range. As a result, for example, when the reference voltage Vref_NTc is lower than the minimum operating voltage of the CMOS transistor of the peripheral circuit 40, the peripheral circuit 40 It is no longer possible to operate in response to commands, etc., entered in the standby state. Therefore, the second embodiment provides a voltage generating circuit that can autonomously generate a temperature-compensated reference voltage Vref without performing trimming of the reference voltage generating section 110 .

Referring to FIG. 3 , the voltage generation circuit 200 of the second embodiment includes: a reference voltage generation unit 210 that generates a reference voltage Vref; a leakage current monitoring unit 220 that monitors the leakage current I _{LEAK_PERI} of the peripheral circuit 250 in the standby state and generates a corresponding leakage current I _LEAK ; the output voltage control unit 230 receives the reference voltage Vref, and outputs the reference voltage Vref_C controlled according to the leakage current I _LEAK generated by the leakage current monitoring unit 220; and the standby voltage generation unit 240, according to the controlled reference voltage Vref_C to generate the internal supply voltage INTVDD. The peripheral circuit 250 operates at low power consumption by the internal supply voltage INTVDD generated by the standby voltage generator 240 in the standby state, and operates by the internal supply voltage INTVDD generated by the active voltage generator 260 in the active state.

The reference voltage generation unit 210 includes, for example, the BGR circuit shown in FIG. 2 , and supplies the reference voltage Vref to the output voltage control unit 230 . The leakage current monitoring unit 220 generates a leakage current I _LEAK having a constant ratio (ratio) to the leakage current I _{LEAK_PERI} generated in the peripheral circuit 250 in the standby state. The peripheral circuit 250 includes various circuits using CMOS transistors, and these circuits are in a state operable by the internal supply voltage INTVDD from the standby voltage generating unit 240 when the flash memory is in the standby mode. On the other hand, the reduction of the threshold voltage of the transistor and the miniaturization of the transistor make the off-state leakage current (off-state leakage current) flowing between the source and drain of the transistor (including PN junction leakage and gate Therefore, the leakage current of the peripheral circuit 250 in the standby state must be suppressed to a minimum.

In one embodiment, the leakage current monitoring unit 220 includes a CMOS transistor formed by connecting at least one PMOS transistor and an NMOS transistor in series, so as to monitor the leakage current of the peripheral circuit 250 . The respective channel widths of the PMOS transistor and the NMOS transistor have a certain ratio R with respect to the total channel width of the PMOS transistor and the NMOS transistor of the overall CMOS transistor of the peripheral circuit 250 . In other words, the off-state leakage current I _LEAK ×R of the CMOS transistor of the leakage current monitoring unit 220 is similar to the off-state leakage current I LEAK — _PERI of the peripheral circuit 250 .

In order to further improve the accuracy of the leakage current I _LEAK generated by the leakage current monitoring unit 220 , the structure of the CMOS transistor of the peripheral circuit 250 may also be considered. That is, in the off-state leakage of the CMOS transistor, there is an off-state when the PMOS transistor is turned off and the NMOS transistor is turned on when the input signal is at a high (High, H) level as shown in (A) of FIG. 4A Leakage current I _PMOS , and off-state leakage current _{I NMOS} when the input signal is low (Low, L) as shown in (B) of FIG. 4A , when the PMOS transistor is turned on and the NMOS transistor is turned off. The off-state leakage current I _PMOS is different from the off-state leakage current I _NMOS , so the total number S_P of CMOS transistors with PMOS transistors turned off and the total number S_N of CMOS transistors with NMOS transistors turned off in the peripheral circuit 250 are calculated. The leakage current monitoring unit 220 includes a leakage circuit A having a constant ratio to the sum of the channel widths of the PMOS transistors of the total number S_P shown in (C) of FIG. 4A , and a leakage circuit B, The PMOS transistor becomes an off-state leakage transistor. In the leakage circuit B, the NMOS transistor becomes off-state leakage transistor. When the leakage circuit A and the leakage circuit B are connected in parallel, the sum of the leakage current I _PMOS and the leakage current I _NMOS becomes the leakage current I _LEAK .

The leakage current monitoring unit 220 may also include various types of leakage circuits to generate the leakage current I _LEAK in consideration of more leakage characteristics of the peripheral circuit 250 . Various logic circuits (inverters, AND gates, NAND gates, etc.) using CMOS transistors are formed in the peripheral circuit 250 , and each logic circuit has a different leakage current. Therefore, as shown in FIG. 4B(A), various leakage circuits A, B, C to N with different leakage characteristics can be prepared, and the one selected by the trimming signal Trim can be selected according to the structure of the peripheral circuit 250. The leaky circuit operates.

For example, leakage circuit A generates the off-state leakage current of the PMOS transistor, leakage circuit B generates the off-state leakage current of the NMOS transistor, leakage circuit C generates the off-state leakage current of the PMOS transistor and the NMOS transistor, and leakage circuit N generates the off-state leakage current of the NMOS transistor. And gate The off-state leakage current of a PMOS transistor. The trimming signal Trim, for example, operates leakage circuits A to N selected by blowing a fuse.

In addition, each of the leakage circuit A, leakage circuit B, leakage circuit C, ..., leakage circuit N performs scale conversion (scaling) on the ratio of the leakage current of the corresponding logic circuit in the peripheral circuit 250, so it includes multiple sets of CMOS transistors, A selected number of CMOS transistors from the plurality of groups of CMOS transistors are operated. The selection is made by the trimming signal Trim. For example, in the case of P groups of leakage circuits A connected in parallel, in order to obtain a certain ratio with respect to the leakage current of the corresponding CMOS inverter of the peripheral circuit 250, the number selected from the P group by the trimming signal Trim The leakage circuit A operates. For example, the number of leakage circuits A selected by blowing the fuses by the trim signal Trim is operated.

Leakage circuit A, leakage circuit B, leakage circuit C, ..., leakage circuit N are connected in parallel, and the sum of leakage current I _A , leakage current I _B , leakage current I _C , ..., leakage current I _N generated by each leakage circuit becomes the leakage current Current I _LEAK . When the operating temperature increases, the leakage current I _LEAK increases, and when the operating temperature decreases, the leakage current I _LEAK decreases.

In this way, the leakage current monitoring unit 220 generates the leakage current I _LEAK obtained by monitoring the leakage current I _{LEAK_PERI} of the peripheral circuit 250 in the standby state, and supplies the generated leakage current I _LEAK to the output voltage control unit 230 .

The output voltage control unit 230 controls the reference voltage Vref according to the leakage current _ILEAK . Specifically, when the leakage current I _LEAK increases, the output voltage control unit 230 decreases the reference voltage Vref_C, and when the leakage current I _LEAK decreases, the output voltage control unit 230 increases the reference voltage Vref_C. The reference voltage Vref_C controlled by the output voltage control unit 230 is supplied to the standby voltage generation unit 240 .

Standby voltage generating unit 240 has, for example, the same configuration as internal voltage generating circuit 120 shown in FIG. 2 . The standby voltage generator 240 receives the reference voltage Vref_C, and supplies the internal supply voltage INTVDD equal to the reference voltage Vref_C to the peripheral circuit 250 . When the operating temperature of the peripheral circuit 250 rises, the reference voltage Vref_C decreases, and accordingly, the internal supply voltage INTVDD decreases, so the leakage current _{ILEAK_PERI} of the peripheral circuit 250 is suppressed, thereby achieving power saving. When transitioning from the standby state to the active state, the internal supply voltage INTVDD is supplied from the active voltage generating unit 260 to the peripheral circuit 250 .

FIG. 5 is a detailed circuit schematic diagram of the voltage generating circuit 200 of the second embodiment. The reference voltage generation part 210 generates a reference voltage Vref using a BGR circuit, and supplies the reference voltage Vref to the output voltage control part 230 . Furthermore, unlike the reference voltage Vref_NTc of the first embodiment, the reference voltage Vref has a positive temperature coefficient.

Like standby voltage generator 240, output voltage controller 230 includes a constant current circuit (unity gain buffer OP1, transistor Q2), and generates voltage Vref on node N3 independent of fluctuations in external power supply voltage VDD. The resistor R3 is connected between the node N3 and the node N4, and generates a constant current I _C at the node N4. The constant current I _C has a constant ratio (I _{LEAK_PERI} : I _LEAK =I _{C_PERI} : I _C ) to the constant current I _{C_PERI} generated by the standby voltage generator 240 . That is, the channel width of the transistor Q2 is adjusted to a certain ratio with respect to the channel width of the transistor Q1.

The leakage current monitoring unit 220 is connected to a node N4 of the output voltage control unit 230 . Here, an example in which leakage current monitoring unit 220 includes leakage circuit A is shown. The constant current I _C generated at the node N4 flows to GND due to the leakage current I _LEAK generated by the leakage current monitoring unit 220. As a result, the difference between the constant current I _C and the leakage current I _LEAK (I _C −I LEAK ) is generated at the node N4. _LEAK ) controlled reference voltage Vref_C. That is, when the leakage current I _LEAK increases due to temperature rise, the reference voltage Vref_C decreases, and when the leakage current I _LEAK decreases due to temperature decrease, the reference voltage Vref_C increases, thereby autonomously generating a controlled reference voltage corresponding to the temperature change. Voltage Vref_C.

In the second embodiment, the reference voltage Vref_C is automatically changed according to the temperature change, but since the leakage current will increase sharply at a certain temperature, the reference voltage Vref_C may be lower than the minimum operating voltage of the CMOS of the peripheral circuit 250 . Therefore, feedback control such that the reference voltage Vref_C is prevented from falling below the lowest operating voltage of the CMOS is performed in the third embodiment.

Referring to FIG. 6, the voltage generation circuit 200A of the third embodiment includes a voltage drop detection unit 300 and an output voltage control unit 310, in addition to a reference voltage generation unit 210, a leakage current monitoring unit 220, a standby voltage generation unit 240 and a second The embodiment is the same.

The voltage drop detection unit 300 monitors the temperature-compensated reference voltage Vref_C output from the output voltage control unit 310, and detects that the reference voltage Vref_C drops to a threshold voltage Vth near the minimum operating voltage Vmin of CMOS (Vref_C-Vmin≦ threshold voltage Vth), and provide the detection result to the output voltage control unit 310 .

Like the second embodiment, the output voltage control section 310 outputs the reference voltage Vref_C corresponding to the leakage current I _LEAK of the leakage current monitoring section 220, but when it is detected that the reference voltage Vref_C has dropped to the threshold voltage Vth, the reference voltage Vref_C is controlled. voltage Vref_C such that the reference voltage Vref_C becomes greater than the threshold voltage Vth. In one embodiment, the output voltage control unit 310 cancels the leakage current I _LEAK by increasing the constant current _IC flowing from the external power supply voltage VDD to the node N3 , thereby increasing the reference voltage Vref_C. In another embodiment, the output voltage control unit 310 increases the reference voltage Vref_C by shifting a direct current (DC) voltage. As a result, the internal supply voltage INTVDD of the standby voltage generator 240 is prevented from falling below the minimum operating voltage of CMOS, and the operation of the peripheral circuit 250 is ensured.

FIG. 7 is a diagram showing a first configuration example of a voltage generating circuit 200A according to a third embodiment of the present invention, and the same reference numerals are assigned to the same configuration as that of FIG. 5 . The voltage drop detection unit 300 monitors the temperature-compensated reference voltage Vref_C of the node N4. The voltage drop detection unit 300 includes a PMOS transistor Q3 whose source is connected to the node N4, a resistor R4 connected between the transistor Q3 and the ground to flow a constant current, and a node N5 connected between the transistor Q3 and the resistor R4. Inverter IN. The gate of the transistor Q3 is grounded, and the transistor Q3 is turned on.

When the reference voltage Vref_C is sufficiently higher than the lowest operating voltage of CMOS, the transistor Q3 is strongly turned on, so that the node N5 becomes H level, and the output of the inverter IN becomes L level. When the reference voltage Vref_C decreases to become Vref_C-Vmin≦Vth, the gate-source voltage V _GS of transistor Q3 decreases, the drain current of transistor Q3 decreases, node N5 becomes L level, and the reverse The output of the phaser IN becomes H level.

The output voltage control unit 310 includes an NMOS transistor Q4 connected in parallel with the transistor Q2 between the external supply voltage VDD and the node N3 , and the gate of the transistor Q4 is connected to the output of the inverter IN of the voltage drop detection unit 300 . When the reference voltage Vref_C decreases and the output of the inverter IN becomes H, the transistor Q4 is turned on and supplies the current I _ADD to the node N3. The size of the transistor Q4 is adjusted in such a way that the current I _ADD cancels the leakage current I _LEAK which increases sharply with temperature, and the reference voltage Vref_C becomes higher than the level detected by the voltage drop detection part 300 .

When the reference voltage Vref_C is sufficiently increased compared with the lowest operating voltage of CMOS, the output of the inverter IN of the voltage drop detection unit 300 becomes L level, and the supply of the current I _ADD is stopped. Furthermore, the method of supplying the current I _ADD is not limited to the method described above, and can also be performed by other methods.

FIG. 8 is a diagram showing a second configuration example of the voltage generating circuit 200A according to the third embodiment of the present invention, and the same reference numerals are assigned to the same configuration as that of FIG. 7 . In the second configuration example, the output voltage control unit 310A includes a voltage offset unit 320 that increases the voltage of the reference voltage Vref_C in the positive direction based on the output of the inverter IN of the voltage drop detection unit 300 . The voltage offset unit 320 includes, for example, a pull-up transistor for connecting the reference voltage Vref_C to the external power supply voltage VDD, and the transistor is turned on in response to the output of the H level of the inverter IN to make the reference voltage Vref_C offset in the positive direction.

When the reference voltage Vref_C is sufficiently increased compared to the lowest operating voltage of the CMOS, the output of the inverter IN of the voltage drop detection unit 300 becomes L level, and the voltage offset by the voltage offset unit 320 is stopped. Furthermore, the method of voltage offset is not limited to the above-mentioned method, and other methods can also be used.

FIG. 9 is a diagram showing a third configuration example of a voltage generating circuit 200A according to a third embodiment of the present invention, and the same reference numerals are assigned to the same configurations as those in FIGS. 7 and 8 . In the third configuration example, the output voltage control unit 310B includes the transistor Q4 shown in FIG. 7 for supplying the current I _ADD and the voltage offset Q4 shown in FIG. 8 for offsetting the reference voltage Vref_C in the positive direction Section 320. The transistor Q4 and the voltage offset unit 320 increase the reference voltage Vref_C in response to the drop of the reference voltage Vref_C detected by the voltage drop detection unit 300 to avoid being lower than the minimum operating voltage of CMOS. According to the third configuration example, the reference voltage Vref_C can be increased in a short time compared with the first configuration example and the second configuration example.

Next, a fourth embodiment of the present invention will be described. FIG. 10 is a schematic diagram showing a voltage generating circuit of the fourth embodiment, and the same reference numerals are assigned to the same configurations as those in FIG. 9 . In the voltage generation circuit 400 of this embodiment, the output voltage generation unit 410 includes a transistor Q10 of the BGR circuit of the reference voltage generation unit 210 and a PMOS transistor Q5 forming a current mirror with the transistor Q20 . The transistor Q5 is connected between the external power supply voltage VDD and the transistor Q2, and the gate of the transistor Q5 is commonly connected to the gates of the transistor Q10 and the transistor Q20.

Transistor Q5 is configured to have a constant current mirror ratio K with respect to transistors Q10/Q20, and current IC flowing to output voltage control unit 410 _is K times iBGR (K is a value equal to or greater than 1). In addition, since the current (iBGR) flowing in the BGR circuit has a positive temperature coefficient, the current _IC flowing to the output voltage control unit 410 also has a positive temperature coefficient. Therefore, when the temperature rises, the current I _C increases, and at the same time, the leakage current I _LEAK generated by the leakage current monitoring unit 220 also increases, and as a result, the reference voltage Vref_C is prevented from dropping rapidly. Furthermore, although the output voltage control unit 410 includes the transistor Q4 that adds the current I _ADD in response to the detection result of the voltage drop detection unit 300 and the voltage offset unit 320 , any one of them may be included.

Next, a fifth embodiment of the present invention will be described. FIG. 11 is a schematic diagram showing a voltage generating circuit according to a fifth embodiment, and the same reference numerals are assigned to the same configurations as those in FIG. 10 . In the voltage generation circuit 500 of this embodiment, the reference voltage generation unit 210A has the same configuration as that of the first embodiment. That is, the reference voltage generation part 210A supplies the reference voltage Vref_NTc having a negative temperature coefficient to the output voltage control part 410 .

In this embodiment, when the temperature rises, the reference voltage Vref_NTc decreases, on the other hand, the current I _C increases, and the leakage current I _LEAK also increases. If the increase of the current _IC is offset by the leakage current _ILEAK , the reference voltage Vref_C decreases due to the decrease of the reference voltage Vref_NTc, and the leakage current of the peripheral circuit 250 is suppressed. Furthermore, although the output voltage control unit 410 includes the transistor Q4 that adds the current I _ADD in response to the detection result of the voltage drop detection unit 300 and the voltage offset unit 320 , any one of them may be included.

The features of the voltage generating circuit of this embodiment are summarized as follows.

1. The internal supply voltage INTVDD of the standby voltage generating unit 240 ensures the minimum operating voltage of CMOS in the entire range where temperature compensation is performed.

2. At the highest temperature in the temperature compensation range, the internal supply voltage INTVDD of the standby voltage generator 240 is controlled to the minimum DC level.

3. By using a lower internal supply voltage INTVDD, the junction leakage current, gate leakage current, and transistor off-state leakage current of the integrated circuit in the peripheral circuit 250 can be reduced suppressed to a minimum.

4. By maintaining a lower level internal supply voltage INTVDD instead of cutting off the power supply in deep power saving mode (DPD), compared with deep power saving mode, the time to return to active operation can be shortened.

In addition, the voltage generating circuit of this embodiment is applied to the standby state of the flash memory, but this is an example, and the present invention can be applied to the voltage supply to the internal circuit regardless of the standby state. Furthermore, the present invention can be applied to a voltage generation circuit that supplies a desired internal voltage to an internal circuit of a semiconductor device other than a flash memory.

Preferred embodiments of the present invention have been described in detail, but the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

200A: Voltage generating circuit

210: Reference voltage generation unit

220: Leakage current monitoring department

240: standby voltage generation unit

250: peripheral circuit

300: voltage drop detection unit

310: output voltage control unit

I _LEAK : Leakage current

INTVDD: Internal supply voltage

Vref: reference voltage

Vref_C: reference voltage after control

Claims (17)

A voltage generating circuit comprising: a reference voltage generating unit generating a reference voltage; a leakage current monitoring unit generating a monitoring leakage current corresponding to a leakage current of an internal circuit of a semiconductor device; and a control unit based on the monitoring leakage current. The reference voltage is controlled; and an internal voltage generation unit receives the reference voltage controlled by the control unit, and supplies an internal voltage to the internal circuit according to the controlled reference voltage. The voltage generation circuit according to claim 1, further comprising a detection unit that detects that the controlled reference voltage has dropped to a certain level, and the control unit, based on the detection result of the detection unit, The controlled reference voltage is controlled. The voltage generating circuit according to claim 2, wherein the certain level is a voltage higher than a lowest operating voltage of a CMOS transistor of the internal circuit. The voltage generating circuit according to claim 1 or 2, wherein the leakage current monitoring part includes a monitoring transistor for generating a monitoring leakage current and performing off-state leakage, and the channel width of the monitoring transistor is configured as There is a certain ratio to the channel width of the total number of transistors that perform off-state leakage in the internal circuit. The voltage generating circuit according to claim 1 or 2, wherein the leakage current monitoring section includes a plurality of monitoring transistors for off-state leakage, and each monitoring transistor The channel width of is configured to have a certain ratio with respect to the channel width of the total number of corresponding off-state leakage transistors of the internal circuit. The voltage generating circuit according to claim 4, wherein the transistor for monitoring is a complementary metal oxide semiconductor transistor formed by connecting a positive channel metal oxide semiconductor transistor and a negative channel metal oxide semiconductor transistor in series . The voltage generation circuit according to claim 1 or 2, wherein the leakage current monitoring unit includes a plurality of types of leakage circuits, and generates a leakage current for monitoring by operating a leakage circuit selected from the plurality of types of leakage circuits. The voltage generating circuit according to claim 7, wherein the leakage current monitoring unit selects a leakage circuit based on a trimming signal input from the outside. The voltage generation circuit according to claim 1 or 2, wherein the control unit includes a constant current circuit that generates a constant current, the output node of the constant current circuit is connected to the leakage current monitoring unit, and the output node outputs the The reference voltage after the above control. The voltage generation circuit according to claim 9, wherein the controlled reference voltage decreases when the monitoring leakage current increases, and the controlled reference voltage increases when the monitoring leakage current decreases. The voltage generation circuit according to claim 9, wherein the constant current circuit generates the constant current according to a reference voltage with a negative temperature coefficient. The voltage generating circuit according to claim 9, wherein the constant current circuit generates the constant current according to a reference voltage having a positive temperature coefficient. The voltage generating circuit according to claim 2, wherein the control unit raises the controlled voltage when the detection unit detects that the controlled voltage has dropped to a certain level . The voltage generation circuit according to claim 13, wherein the control unit adds an additional current to the constant current based on the detection result of the detection unit. The voltage generating circuit according to claim 13, wherein the control unit increases the controlled reference voltage in a positive direction according to the detection result of the detection unit. A semiconductor device including the voltage generating circuit according to any one of claims 1 to 15. The semiconductor device according to claim 16 includes a standby mode that operates under low power consumption, and the voltage generating circuit supplies an internal voltage to an internal circuit in the standby mode.

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